Kinetika reakcija demetilacije aglikona flavonoida posredovanih citokromima P450 3A4 i 2D6

master's thesis

• Title (english): Kinetics of demethylation reactions of flavonoid aglycones mediated by cytochromes P450 3A4 and 2D6
• Author: Josipa Vučenović
• Mentor: Mirza Bojić (mentor)
• Committee member: Mirza Bojić (predsjednik povjerenstva)
• Committee member: Željan Maleš (član povjerenstva)
• Committee member: Hrvoje Rimac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of medicinal chemistry); Zagreb
• Defense date and country: 2018-04-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Flavonoidi su velika skupina spojeva, čiji su glavni izvori voće i povrće. Osnovu strukture čine dva benzenska
prstena povezana piranskim prstenom. Dalje se flavonoidi dijele u različite podskupine, ovisno o položaju
vezanja prstenova i o supstituentima. Flavonoidi su otkriveni puno prije negoli je interes za njihova istraživanja
porastao, a to se dogodilo zbog saznanja da imaju jako antioksidativno djelovanje. Danas se istražuju njihov
metabolizam, učinak na prevenciju nekih bolesti kao što su različite vrste raka, srčane bolesti i dijabetes.
Metabolizam flavonoida odvija se preko CYP enzima, što ispitivanja na tom području čini bitnima za prevenciju
interakcija, budući da se pokazalo da flavonoidi mogu inhibirati i inducirati ovu superporodicu enzima.
Za potrebe ovog rada ispitane su reakcije demetilacije flavonoida enzimima CYP2D6 i 3A4. Izabrani flavonoidi
su sakuranetin, akacetin i tangeretin. Za identifikaciju metabolita korištena je spregnuta tehnika, LC-MS s DAD i
Q-TOF detektorom, jer daje pouzdane podatke o molekulskoj masi i strukturi metabolita. U svrhu kvantifikacije
produkata korištene su kalibracijske krivulje kvercetina. Kinetika reakcije određena je Michaelis-Mentenčinom
jednadžbom te su iskazane vrijednosti Vmax i Km. Pokazalo se da tangeretin daje produkte demetilacije s oba
enzima, a veću katalitičku efikasnost ima CYP3A4. Sakuranetin se ne demetilira s CYP3A4, a akacetin se
metabolizira enzimom CYP2D6 do apigenina.
Ispitani flavonoidi imaju potencijal interakcija preko citokroma P450 3A4 i 2D6. Uzimajući u obzir i
polimorfizam enzima CYP2D6, ovi rezultati bitni su za bolje razumijevanje metabolizma flavonoida,
predviđanje i sprječavanje međudjelovanja s drugim spojevima.

Abstract (english)

Flavonoids are a large group of compounds, that people ingest through fruit and vegetables. The basic structure
of flavonoids consists of two benzene rings which are connected by a pyran. These compounds are devided in
many subgroups, depending on the position of ring connection and substituents. Flavonoids were discovered
years before the interest in their research intensified because of the discovery of their strong antioxidant activity.
Most of researches are focused on their metabolism and prevention of cancer, diabetes and heart diseases.
Flavonoids are metabolised by cytochrome P450 enzymes. Metabolism mediated by CYP enzymes indicates a
strong possibility of interactions and thorough studies are important in order to prevent them, considering the
fact that inhibitory and inductive CYP activity of flavonoids persists.
Three flavonoids were selected in order to study demethylation kinetics by enzymes CYP2D6 and 3A4. Selected
flavonoids were sakuranetin, tangeretin and acacetin. Because of the possibility to give precise molecular mass
and structure of metabolites, the chosen metode of identification was LC-MS connected to DAD and Q-TOF
detector. For quantification calibration curves of quercetin were used. Reaction kinetic was determined by
Michaelis- Menten equation. The study has shown that tangeretin gives demethylation products when incubated
with both, CYP3A4 and 2D6 enzymes, but greater efficacy of catalysis is related to CYP3A4. Sakuranetin is not
demethylated by CYP3A4 and acacetin has one demethylation by CYP2D6 metabolite, apigenin.
Flavonoids that have been studied have potential to interact via cytochrome P450 metabolism. Taking the
polimorfism of CYP2D6 in consideration, these results are important for predicting and preventing flavonoid drug
interactions.

• Keywords: flavonoidi; CYP3A4; CYP 2D6
• Keywords (english): flavonoids; CYP3A4; CYP 2D6
• Language: croatian
• URN:NBN: urn:nbn:hr:163:679954
• Study programme: Title: Pharmacy; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-04-19 10:05:30